From d8bc3bfb6d6618f8b6b0669cb5051f85192e5978 Mon Sep 17 00:00:00 2001
From: Pierre Bourdon <delroth@gmail.com>
Date: Thu, 23 May 2024 02:52:54 +0200
Subject: [PATCH] repl: do not crash when tab-completing import errors

File not found while importing causes a SysError, not an EvalError,
which is not currently caught by the tab-completion handler. Ignoring
all SysErrors might seem "dangerous" but this is the tab-completion
handler, any exception being bubbled up from there causes unexpected
behavior (causes the whole repl to exit).

Fixes #340.

Change-Id: I643048a47935e77f582decc539d9e51bdb96c890
---
 src/libcmd/repl.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/libcmd/repl.cc b/src/libcmd/repl.cc
index 525c25560..a74ea8e5f 100644
--- a/src/libcmd/repl.cc
+++ b/src/libcmd/repl.cc
@@ -375,6 +375,9 @@ StringSet NixRepl::completePrefix(const std::string & prefix)
             // Quietly ignore evaluation errors.
         } catch (BadURL & e) {
             // Quietly ignore BadURL flake-related errors.
+        } catch (SysError & e) {
+            // Quietly ignore system errors which can for example be raised by
+            // a non-existent file being `import`-ed.
         }
     }